feat: refine ruleset from a full-project field review (#39)

* feat: refine ruleset from a full-project field review

A reviewer ran ponytail across a 9-phase rewrite (protocol, PC app, simulator,
RPi daemon, ESP32 firmware) and flagged three gaps. All three land in SKILL.md
and propagate to AGENTS.md + the rule copies:

- Promote the one-runnable-check rule to a headline ("Lazy code without its
  check is unfinished"), enforced as a check-rule-copies invariant.
- Hardware carve-out in "When NOT to be lazy": a real device is never the spec
  ideal (clock drift, sensor offset), leave the calibration knob.
- Clarify the Output rule: explanation the user explicitly asked for is not
  debt, only unrequested prose is.

Fallback instructions kept in sync. Rule-copy check + tests green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* test: add a behavior gate proving the refinements actually fire

The refinements were verified as injected text, but injected != behavioral.
This adds a behavior eval that probes each refined rule on a task that should
trigger it:

- hardware    -> does the output leave a calibration knob?
- explanation -> when a write-up is explicitly requested, is it given in full?
- onecheck    -> is a runnable check left behind?

benchmarks/behavior.yaml runs the probes (baseline vs ponytail arm); the
grader benchmarks/behavior.js is proven by tests/behavior.test.js (8 cases,
RED/GREEN, no API key, runs in CI). Live-confirmed: the model under the
current ruleset passes all three gates, graded by the same grader.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

benchmarks/behavior.js

@@ -0,0 +1,58 @@
+// Behavior gate: does the ponytail ruleset actually PRODUCE its refined
+// behaviors, not just carry the text? One check per probe (vars.probe), each
+// targeting a rule that a field review (rcstack, phases 0-8) showed mattered:
+//   hardware     - "hardware is never the spec ideal, leave the calibration knob"
+//   explanation  - "explanation the user explicitly asked for is not debt"
+//   onecheck     - "lazy code without its check is unfinished"
+//
+// Heuristic graders, same spirit as loc.js / correctness.js. The graders
+// themselves are proven by tests/behavior.test.js (RED/GREEN, no API key).
+//
+// Metric: `behavior` (1 = behavior present, 0 = absent).
+
+function codeOf(text) {
+  return [...String(text || '').matchAll(/```[\w-]*\n([\s\S]*?)```/g)].map((m) => m[1]).join('\n');
+}
+
+function proseOf(text) {
+  return String(text || '').replace(/```[\s\S]*?```/g, ' ').replace(/\s+/g, ' ').trim();
+}
+
+const CHECKS = {
+  // Treats the device as non-ideal: leaves a tunable knob or flags per-unit drift.
+  // A passing mention of "calibration" is not enough; it must be actionable.
+  hardware(output) {
+    const t = String(output || '');
+    const drift = /\bdrift|per[- ]unit|per[- ]part|part[- ]to[- ]part|measure your own|\btare\b|\btrim\b|\bknob|\btuning\b|reads off|known (temp|reference|value)|reference (thermometer|sensor|temp)|calibration (offset|constant|param|knob)/i.test(t);
+    return drift
+      ? { pass: true, reason: 'Leaves a calibration knob / flags per-unit drift.' }
+      : { pass: false, reason: 'Treats the hardware as ideal; no calibration knob.' };
+  },
+
+  // Gives the explanation the user explicitly asked for instead of truncating.
+  explanation(output) {
+    const p = proseOf(output);
+    const words = p ? p.split(' ').length : 0;
+    const structured = /(\d+[.)]\s|[-*]\s)/.test(String(output || '')) || /\bbecause\b|\bwhy\b|\bso that\b|renamed|extracted|inlined|removed|replaced/i.test(p);
+    return words >= 45 && structured
+      ? { pass: true, reason: `Gave the requested write-up (${words} words of prose).` }
+      : { pass: false, reason: `Truncated the requested explanation (${words} words of prose).` };
+  },
+
+  // Leaves ONE runnable check behind for non-trivial logic.
+  onecheck(output) {
+    const t = String(output || '');
+    const hasCheck = /\bassert\b|def\s+test_|if\s+__name__|unittest|pytest|console\.assert|\bexpect\(|\bdescribe\(|\bit\(/.test(t);
+    return hasCheck
+      ? { pass: true, reason: 'Left a runnable check (assert/test/demo).' }
+      : { pass: false, reason: 'No runnable check left behind.' };
+  },
+};
+
+module.exports = (output, context) => {
+  const probe = context && context.vars && context.vars.probe;
+  const check = CHECKS[probe];
+  if (!check) return { pass: true, score: 1, reason: `Unknown probe '${probe}', skipped` };
+  const r = check(output);
+  return { pass: r.pass, score: r.pass ? 1 : 0, reason: r.reason };
+};